This invention relates to the processing of seismic data to render it more useful in interpreting the seismic characteristics of the earth in the exploration for oil and gas deposits.
In seismic prospecting a seismic energy source is employed to generate a seismic signal which is transmitted into the earth. A portion of this signal is reflected from reflecting interfaces within the earth back toward the surface of the earth where it is received by detector stations positioned to receive the reflected signals. There are many different types of seismic energy sources employed in seismic prospecting. In general, these energy sources may be classified in two general classes, those by which an impulse signal is transmitted into the earth, and those by which vibrational energy is transmitted by a continuous or semicontinuous process into the earth. The detector stations are usually comprised of a group of geophones which generate electrical signals in response to received seismic signals. The geophones are electrically connected with seismic recording instruments for recording the electrical signals. A recording of one seismic channel is referred to as a trace or seismic trace. When the trace is recorded in analog form on a magnetic tape there is a continuous record written on the tape of an output voltage of a seismic amplifier used in conjunction with the recording of the electrical signals generated by the geophones. When processed in analog form these electrical signals are operated upon for example by filtering to present them in form for use by geophysicists. With the digital recording of seismic data a discontinuous record of the signal is written that measures the seismic amplifier output voltage only at discrete intervals. The digitally recorded data may be operated upon to present the data in form for use by geophysicists. Reference may be had to "A Pictorial Digital Atlas", 1966 Edition, prepared by Staff Members of United Geophysical Corporation, and presented at the 36th Annual Meeting of the SEG, Houston, Tex., November 1966, for a better understanding of digital recording and analysis and processing of seismic signals.